More changes to Rdbadmin and Rdbhost

A few recent improvements to Rdbadmin:

• Main page shows tables and fields.
• New section of left-hand menu shows schemas.
• Menu options create and rename schemas.

Improvements to Rdbhost:

• Login page (and login link from front page) is https.
• Login cookie is 'secure' so will not be available to non-https pages.
• Attempting to access another account while logged into yours will result in an error. You must log out of your account to access any other.